Buggy code:
public static final long Bit48L = 140737488355328L ; public static final long Bit49L = 281474976710656L ; public static final long Bit50L = 562949953421312L ; public static final long Bit51L = 1125899906842624L ; public static final long Bit52L = 2251799813685248L ; public static final long Bit53L = 4503599627370496L ; public static final long Bit54L = 9007199254740992L ; public static final long Bit55L = 18014398509481984L ; public static final long Bit56L = 36028797018963968L ; public int bits = ASTNode . IsReachableMASK ; public static final int ReturnTypeIDMASK = ( ( ( ASTNode . Bit1 ) | ( ASTNode . Bit2 ) ) | ( ASTNode . Bit3 ) ) | ( ASTNode . Bit4 ) ; public static final int OperatorSHIFT = 6 ; public static final int OperatorMASK = ( ( ( ( ( ASTNode . Bit7 ) | ( ASTNode . Bit8 ) ) | ( ASTNode . Bit9 ) ) | ( ASTNode . Bit10 ) ) | ( ASTNode . Bit11 ) ) | ( ASTNode . Bit12 ) ; public static final int ValueForReturnMASK = ASTNode . Bit5 ; public static final int OnlyValueRequiredMASK = ASTNode . Bit6 ; public static final int UnnecessaryCastMASK = ASTNode . Bit15 ; public static final int IgnoreNeedForCastCheckMASK = ASTNode . Bit6 ; public static final int NeedRuntimeCheckCastMASK = ASTNode . Bit7 ; public static final int UnsafeCastMask = ASTNode . Bit8 ; public static final int RestrictiveFlagMASK = ( ( ASTNode . Bit1 ) | ( ASTNode . Bit2 ) ) | ( ASTNode . Bit3 ) ; public static final int FirstAssignmentToLocalMASK = ASTNode . Bit4 ; public static final int IsImplicitThisMask = ASTNode . Bit3 ; public static final int DepthSHIFT = 5 ; public static final int DepthMASK = ( ( ( ( ( ( ( ASTNode . Bit6 ) | ( ASTNode . Bit7 ) ) | ( ASTNode . Bit8 ) ) | ( ASTNode . Bit9 ) ) | ( ASTNode . Bit10 ) ) | ( ASTNode . Bit11 ) ) | ( ASTNode . Bit12 ) ) | ( ASTNode . Bit13 ) ; public static final int IsReachableMASK = ASTNode . Bit32 ; public static final int IsLocalDeclarationReachableMASK = ASTNode . Bit31 ; public static final int AddAssertionMASK = ASTNode . Bit1 ; public static final int IsLocalTypeMASK = ASTNode . Bit9 ; public static final int IsAnonymousTypeMASK = ASTNode . Bit10 ; public static final int AnonymousAndLocalMask = ( ASTNode . IsAnonymousTypeMASK ) | ( ASTNode . IsLocalTypeMASK ) ; public static final int IsMemberTypeMASK = ASTNode . Bit11 ; public static final int HasAbstractMethods = ASTNode . Bit12 ; public static final int HasLocalTypeMASK = ASTNode . Bit2 ; public static final int ParenthesizedSHIFT = 21 ; public static final int ParenthesizedMASK = ( ( ( ( ( ( ( ASTNode . Bit22 ) | ( ASTNode . Bit23 ) ) | ( ASTNode . Bit24 ) ) | ( ASTNode . Bit25 ) ) | ( ASTNode . Bit26 ) ) | ( ASTNode . Bit27 ) ) | ( ASTNode . Bit28 ) ) | ( ASTNode . Bit29 ) ; public static final int IsAssignmentWithNoEffectMASK = ASTNode . Bit30 ; public static final int IsStrictlyAssignedMASK = ASTNode . Bit14 ; public static final int IsCompoundAssignedMASK = ASTNode . Bit17 ; public static final int IsUsefulEmptyStatementMASK = ASTNode . Bit1 ; public static final int UndocumentedEmptyBlockMASK = ASTNode . Bit4 ; public static final int HasAllMethodBodies = ASTNode . Bit5 ; public static final int InsideJavadoc = ASTNode . Bit16 ; public static final int IsElseIfStatement = ASTNode . Bit30 ; public static final int IsSuperType = ASTNode . Bit5 ; public static final int IsVarArgs = ASTNode . Bit15 ; public static final int IsAnnotationDefaultValue = ASTNode . Bit1 ; public ASTNode ( ) { } private static boolean checkInvocationArgument ( BlockScope scope , Expression argument , TypeBinding parameterType , TypeBinding argumentType , TypeBinding originalParameterType ) { } public static void checkInvocationArguments ( BlockScope scope , Expression receiver , TypeBinding receiverType , MethodBinding method , Expression [ ] arguments , TypeBinding [ ] argumentTypes , boolean argsContainCast , InvocationSite invocationSite ) { } public ASTNode concreteStatement ( ) { } public final boolean isFieldUseDeprecated ( FieldBinding field , Scope scope , boolean isStrictlyAssigned ) { if ( ( ( ! isStrictlyAssigned ) && ( ( field . isPrivate ( ) ) || ( ( ( field . declaringClass ) != null ) && ( field . declaringClass . isLocalType ( ) ) ) ) ) && ( ! ( scope . isDefinedInField ( field ) ) ) ) { <START_BUG> field . modifiers |= AccLocallyUsed ; <END_BUG> } if ( ! ( field . isViewedAsDeprecated ( ) ) ) return false ; if ( scope . isDefinedInSameUnit ( field . declaringClass ) ) return false ; if ( ( ! ( scope . compilerOptions ( ) . reportDeprecationInsideDeprecatedCode ) ) && ( scope . isInsideDeprecatedCode ( ) ) ) return false ; return true ; } public boolean isImplicitThis ( ) { } public final boolean isMethodUseDeprecated ( MethodBinding method , Scope scope ) { } public boolean isSuper ( ) { } public boolean isThis ( ) { } public final boolean isTypeUseDeprecated ( TypeBinding type , Scope scope ) { } public abstract StringBuffer print ( int indent , StringBuffer output ) { } public static StringBuffer printAnnotations ( Annotation [ ] annotations , StringBuffer output ) { } public static StringBuffer printIndent ( int indent , StringBuffer output ) { } public static StringBuffer printModifiers ( int modifiers , StringBuffer output ) { } public static void resolveAnnotations ( BlockScope scope , Annotation [ ] annotations , Binding recipient ) { } public int sourceStart ( ) { } public int sourceEnd ( ) { } public String toString ( ) { } public void traverse ( ASTVisitor visitor , BlockScope scope ) { } }

Fix:
field . original ( ) . modifiers |= AccLocallyUsed ;